Intermediate-frequency coupling unit



March 15, 1 938. F. N. JACOB INTERMEDIATE FREQUENCY COUPLING UNIT Filed Aug. 6. 1955 16 16 lll mllIlJiei 17 19 IIIII||I|I 9 I 5% QE' E 17 15a j 17a i E 74 Ex:

6 I 6 id 10 5 L, g Z *5 f INVENTOR, Fesuze/ck/yjq C05,

ATTORNEY.

Patented Mar. 15, 1938 Frederick N. Jacob, ilhicago, 111., assignor to Johnson Laboratories, Inc., Chicago, 111., a corporation oi Illinois Applicationilugust 6, 1935, Serial No. 34,959

Y 14 Claims.

The invention relates to high frequency coupling units such as may be employed in highirequency radio receivers, although it desirably may be used in other apparatus.

Heretofore, a coupling unit of this type has been mounted on a shielded insulating support of Bakelite, or other material, which carriul the coils and the cores oi. the inductances, as well as their associated insulated leads, and fixedly held these leads in their operative positions, to thereby avoid alterations of their mutual inductances. It is an object of this invention to produce a ecupling unit without using such a support, and to utilize uninsulated conductors which are so fixedly related as to maintain their capacitative efiects constant.

In manufacturing these coupling units, it has been customary to extend the natural leads to the terminal lugs of the respective tuning condensers, to then attach the heavy 22-gauge insulated conductors to the lugs, and finally to extend said conductors through the shield of the unit where they are connected with extraneous elements of the radio circuits.

A- disadvantage encountered in utilizing this conventional form of construction, has been that, due 'to vibrations or shocks, elements of the assembly, such as the natural or the hook-up leads of the coils, have not at all times stayed in fixed relation to each other.

One of the objects of my invention, is to provide a high-irequency-coupling unit having very short natural coil leads which are disposed within the shield of said unit, so as to minimize capacity and entirely avoid the undesirable effects of capacity alterations which would otherwise ensue.

In this, my new construction, there are within the shield uninsulated conductive bus bars, each' 0 having a hole at its upper end and one in the middle, which holes serve as anchorages for the coil leads as well as anchorages for the extraneous hook-up leads or insulated conductors.

As will be noted, these bus bars, on account of their-rigidity, are always maintained in spaced relations to each other, and require no insulation which, if present, would produce such dielectric losses as occur when insulated conductors are employed.

Each bus bar not only acts as an anchorage, a conductor and a spacer of other elements of the coupling unit, but also aids in maintaining all of the elements in fixed positions.

Furthermore, in this device it is possible to u make a pre-assembly or the cores, so that by winding the coils simultaneously on a winding machine, the space between the two inductances is kept constant, thereby avoiding the necessity of later adjusting the coupling between the inductors, thus decreasing the cost of manufacture.

The invention will best be understood if reference be had to the accompanying drawing, in which-- Figure 1 is a vertical sectional view showing the intermediate-irequency coupling unit in a shield;

Figure 2 is a view of the device, as seen irom above;

Figure 3 is a view or the device, as seen from below:

Figure 4 is a view diagrammatically showing the conductors and coils which constitute operative elements of the device, and

Figure 5 is a view of one of the bus bars in elevation.

Referring to the drawing, i is a shield which is open at its top and is provided with a closed bottom 2 having a central opening I and a side opening i.

-Within the lower end of said shield i, is disposed a ceramic base 5, carrying on its underside adjustable condensers 6, 8a. The condensers, respectively, are in circuit with conductor coils i, la, which respectively are provided with annular cores 8, 8a. The bottom of the shield I, is provided with-holes la, lb, which give access to the adjusting means of said condensers, as shown in Fig. 3.

A non-conductive rod 9, extending through said annular cores 8, 8a, affords a support for said cores and their inductance coils I, la. The lower end of this rod 9 is enclosed by an internallyflanged non-conductive annulus it which spaces said ceramic base from the lower core 8.

The rod 9 rests on a headed bolt II which extends downward through a hole Illa in said annulus it, through a hole l2 in said ceramic hue 5, and also through the central opening 3 in the bottom 2 of said shield l. The bolt Ii carries near its lower end a washer [3 which is forced against the under surface of said ceramic base 5 by a nut ii that engages the screw-threads oi the bolt ii. A further nut l5 and its washer Ila, carried by said bolt H and disposed below the bottom 2 of said shield i, holds said bolt II in place within said shield.

The upper end of said rod 9 is suitably secured to a thin spacing and supporting element It made of Bakelite or other non-conducting substance, and through this element 18 extend conductive bus bars I1, l8 and it which are fixedly secured to said element II and to-said ceramic base I, thereby constituting struts for holding these two elements and other parts of the device in their proper positions.

These conductive bus bars I], ll, ii, are each provided with a perforated flattened portion lla, Ila, or I 90, disposed at a point substantially midway its length, and are each provided at its free end with a perforated flattened portion I lb, Ilb or ilb.

One terminal lb of the inductance coil la, is threaded through the perforation in the intermediate flattened portion lla of the bus bar l1, and is there soldered in place, while the other terminal lc of said inductance coil la is threaded through the perforation in the intermediate flattened portion lt of the bus bar is, in which it is soldered.

Through the flattened perforated upper end llb of the bus bar I! is threaded the end of an insulated conductor 20 which is disposed outside of the shield i. An insulated conductor 2i, leading from a B-supply, also disposed outside of said shield I, is threaded through the flattened perforated upper end "b, of the bus bar i1, to which bus bar it is soldered.

The circuit formed by the lower portion of the bus bar II, the coil la and the lower portion of the bus bar ll, is shunted by the condenser So, one plate of which carries a lug 8b, to which the proximate end .of said bus bar I! is soldered, the other plate of said condenser being conductively connected to the bus bar I! by a lug 6c. The insulated conductor 20 terminates at the plate of a thermionic tube 23, as shown.

The coil I has one of its leads Id threaded through the aperture Ila of the intermediate flattened portion of the bus bar l9, a conductive path being formed from this point I94, through upper portion oi the bus bar l9, through the insulated conductor 22, and thence to ground.

The other lead of the inductance coil I is connected to a lug ie of the condenser 8, and also to the conductor 24 which, in turn, is connected to the grid of a thermionic tube 25. The other lug Id of the condenser 8 is connected with the bus bar ll.

Having thus described my invention, what I clalmis:

1. In an inductance unit for radio receivers, the combination of a rod of non-conducting material, inductively related high-frequency coils supported on said rod for use in inductively coupled circuits, a head of insulating material at each end of and secured to said rod, and a plurality of metal rods spaced from said supporting rod and from each other and extending between said heads, whereby said heads are held in desired relation to each other and said metal rods are held in flxed pomtion relatively to each other and to said supporting rod and have flxed capacitative coupling with said coils, said metal rods being spaced from said coils and constituting bus bars electrically connected with said coils in inductively coupled circuits and comprising connection terminals of said unit.

2. In an inductance unit for radio receivers, the combination of a rod of non-conducting material, inductively related high-frequency coils supported on said rod for use in inductively coupled circuits, a head of insulating material at each end of and secured to said rod,,and a plurality of metal rods spaced from said supporting rod and from each other and extending between said heads, whereby said heads are held in desired relation to each other and said metal rods are held in flxed position relatively to each other and to said supporting rodand have flxed capacitative coupling with said coils, said metal rods being spaced from said coils and constituting bus bars electrically connected with said coils in inductively coupled circuits and comprising connection terminals of said unit, said metal rods having flattened and perforated mid-portions to facilitate maldng electrical connections with them.

3. In an inductance unit for radio receivers, the combination of a rod of non-conducting material, inductively related high-frequency coils supported on said rod for use in inductively coupled circuits. a head of insulating material at each end of and secured to said rod, a plurality oi metal rods spaced from said supporting rod and from each other andextending between said heads, whereby said heads are held in desired relation to each other and said metal rods are held in fixed position relatively to each other and to said supporting rod and have flxed capacitative coupling with said coils, said metal rods being spaced from said coils and constituting bus bars electrically connected with said coils in inductively coupled circuits and comprising connection terminals of said unit, and condensers mounted on one of said heads and electrically connected with said metal rods in resonant circuits.

4. In a coupling unit for radio receivers, the combination of a first head of insulating material, condensers mounted on said head and having spaced connection lugs, a rod of insulating material secured to and extending from the censaid condenser lugs and extending to and engaging said second head and constituting struts between said heads, said coils being electrically connected with said metal rods to constitute coupled resonant circuits, whereby said metal rods comprise bus bar connectors of said unit, said metal rods being sufliciently rigid to maintain their relationship to each other and to said coils, thereby maintaining substantially constant the capacitative coupling eflects of the wiring connections of said unit.

5. In a coupling unit for radio receivers, the combination of two members of insulating material in substantially parallel relation, an element of non-conducting material extending between and attached to said members and holding the latter in spaced relation. inductively related highfrequency coils supported by said element between said members for use in inductively coupled circuits, and spaced and relatively rigid metal rods extending between said members near said coils and electrically connected respectively adjacent said coils with the terminals of said coils, whereby said metal rods have fixed capacitative coupling with the coils with which they are not connected and constitute bus bar connectors of said unit.

6. In a coupling unit for radio receivers, the combination of two members of insulating material in substantially parallel relation, an element of non-conducting material extending between and attached to said members and holding the latter in spaced relation, inductively related high-frequency coils supported by said element between said members for use in inductively coupled circuits, spaced and relatively rigid metal rods extending between said members near said coils and electrically connected respectively adjacent said coils with the terminals of said coils, whereby said metal rods have fixed capacitative coupling with the coils with which they are not connected and constitute bus bar connectors of 4 said unit, and condensers carried by one of said members and having their terminals connected respectively with first end portions of said metal rods connected with said coils to constitute coupled resonant circuits, said metal rods comprising terminal connectors of said coupling unit.

7. In a tuned coupling unit for radio receivers, the combination of two members of insulating material spaced from each other and in substantially parallel relation, an element of nonconducting material supported between said members, inductively related high-frequency inductance coils supported by said element between said members, cores magnetic material for said coils. relatively rigid metal rods extending between said members near said coils, said rods being spaced from each other and from said coils and electrically connected respectively with terminals 01 said coils, and tuning condensers carried by one of said members and having terminals electrically connected respectively with said metal rods connected with the coils to be tuned by said condensers to form coupled resonant circuits, whereby said metal rods comprise electrical bus bars connecting said coils and condensers and have fixed capacitative coupling with the coils with which they are not connected.

8-. In a tuned coupling unit for radio receivers, the combination or two members of insulating material spaced from each other and in substantially parallel relation, an element of non-conducting material supported between said members, inductively related high-frequency inductance coils supported by said element between said members, cores of magnetic material for said coils, relatively rigid metal rods extending between said members near said coils, said rods being spaced from each other and from said coils and electrically connected respectively with terminals of said coils, and tuning condensers carried by one of said memb rs and having terminals electrically connected respectively with said metal rods connected with the coils to be tuned by said condensers to form coupled resonant circuits. whereby said metal rods comprise electrical bus bars connecting said coils and condensers and have fixed capacitative coupling with the coils with which they are not connected, said condensers having connection terminals connected directly with said metal rods respectively.

9. In a tuned coupling unit for radio receivers, the combination of two members of insulating material spaced from each other and in substantially parallel relation, an element of non-conducting material supported between said members, inductively related high-frequency inductance coils supported by said element between said members, cores of magnetic material for said coils, relatively rigid metal rods extending between said members near said coils, said rods being spaced from each other and from said coils' and electrically connected respectively with terminals of said coils, and tuning condensers carried by one of said members and having terminals electrically connected respectively with said metal rods connected with the coils to be 75 tuned by said condensers to iorm coupled resonant circuits, whereby said metal rods comprise electrical bus bars connecting said coils and condensers and have fixed capaoitative coupling with the coils with which they are not connected, said metal rods comprising connection terminals or the Mud coupling unit.

10. In a tuned coupling unit for radio receivers, the combination of two heads of insulating material spaced irom each other and in substantially parallel relation, a supporting rod of non-conducting material conn'ectlng and secured to central portions of said heads, annular cores 01 mag. netic material on and secured to said supporting rod, high-frequency inductance coils around said cores, the relation 01 said cores inductively re lating said coils, relatively rigid metal rods spaced from each other and from said coils and con-- nected with said'heads, said metal rods being substantially parallel with each other and with said supporting rod and electrically connected respectively with terminals of said coils, and tuning condensers carried by one of said heads and having terminals electrically connected respectively with said metal rods connected with the coils to be tuned by said condensers to form coupled resonant circuits, whereby said metal rods comprise struts between said heads and electrical bus bars connecting said coils and condensers and have fixed capacitative coupling with the coils with which they are not connected.

11. In a tuned coupling unit for radio receivers, the combination or two heads of insulating material spaced from each other and in substantially parallel relation, a supporting rod of non-conducting material connecting and secured to central portions of said heads, annular cores of magnetic material on and secured to said supporting rod, high-frequency inductance coils around said cores, the relation of said cores inductively re lating said coils, relatively rigid metal rods spaced from each other and from said coils and connected with said heads, said metal rods being substan- V tially parallel with each other and with said supporting rod and electrically connected respectively with terminals of said coils, and tuning" condensers carried by one of said heads and having terminals electrically connected respectively with said metal rods connected with the coils to be tuned by said condensers to form coupled resonant circuits, whereby said metal rods comprise struts between said heads and electrical bus bars connecting said coils and condensers and have fixed capacitative coupling with the coils with which they are not connected, said condensers having connection lugs connected directly with said metal rods respectively.

12. In a tuned coupling unit for radio receivers, the combination of two heads of insulating mate rial spaced from each other and in substantially parallel relation, a supporting rod of non-conducting material connecting and secured to central portions of said heads, annular cores of magnetic material on and secured to said supporting rod, high-frequency inductance coils around said cores, the relation of said cores inductively relating said coils, relatively rigid metal rods spaced from each other and from said coils and connect ed with said heads, said metal rods being substantially parallel with each other and with said supporting rod and electrically connected respectively with terminals of said coils, and tuning condensers carried by one of said heads and having terminals electrically connected respectively with said metal rods connected with the coils to be tuned by said condensers to form coupled resonant circuits, whereby said metal rods comprise struts between said heads and electrical bus bars connecting said coils and condensers and have fixed capacitative coupling with the coils with which they are not connected, said metal rods extending through said head remote from said condensers and comprising connection terminals of the tuned coupling unit.

13. In a high-irequency resonant coupling unit for radio receivers, the combination oi. an insulating support. inductance coils mounted in inductive relation to each other on said support, adlustable condensers having fixed relation to said support tor tuning said coils. said condensers having connection terminals, and rigid conductor rods having fixed relation to said support near said coils and connecting the terminals of said coils with the connection terminals of said condensers respectively, thereby establishing fixed capacitative effects between said conductor rods and the other parts 0! said coupling unit, whereby the resonant circuits 0! duplicate coupling units have substantially the same degree 0! cou- Duns.

14. In a high-frequency resonant coupling unit for radio receivers. the combination of a supporting rod of non-magnetic material, annular magnetic cores mounted in fixed position on said rod. inductive windings around said cores. a base oi insulating material secured to one end of said rod,.adiustable condensers mounted on said base for tuning said windings, and rigid metal rods spaced from said windings and held substantially parallel with said supporting rod and with each other and connecting the terminals of said condensers respectively with the terminals of said windings to form coupled resonant circuits, thereby establishing fixed capacitative eiiects between said metal rods and the other parts of said coupling unit, whereby duplicate coupling units have substantially the same degree of coupling.

FREDERICK N. JACOB. 

